As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT MADE A PL BACK TO HOSPITAL PAD WITH A PATIENT ON BOARD AND REPORTED AFTER 2 MINUTES INTO THE FLIGHT WITH CABIN HEAT APPLIED, CABIN BAGAN TO FILL WITH SMOKE ON THE CEILING. MECHANIC TROUBLESHOT AND FOUND EXCESS INLET BARRIER FILTER FLUID IN THE ENGINE INTAKE PLENUM FROM RECENT FILTER SERVICEING. CLEANED EXCESS FLUID AND PERFORMED ENGINE RUNUP WITH HEATER APPLIED AND NO FURTHER DEFECTS.